The process of urbanization started long before the word itself existed. In fact, the relentless pursuit of a more comfortable life has been going on ever since man realized his superiority over the rest of the animals. From caves to huts, then to houses and sky scrapers! Man made them all. In the last couple of centuries many changes have occurred as never before in the entire history of mankind. Maybe these enormous changes are too much and too fast for Mother Nature to cope with, as is reflected in the declining environment around us as well as our own health.

Now and then

It was the 1840s when a cholera epidemic struck and completely paralyzed Europe and America. At this time, people used water from the same source where the sewage from the city was drained. That was how miserable the urban set up was. This incident exemplifies how hard an unplanned and unsettled urbanization can hit human health. In New York alone, the epidemic left 3,515 dead out of then population of 250,000.1 Now the scene has changed, we live in a healthier city. But what we fail to notice is that something different has emerged, which is more complex and threatening than the cholera infection. Take the examples of hypertension and diabetes, which have arisen from our sedentary urban lifestyles.

Different aspects of urbanizationUrban health is not so healthy

Urban climates are distinguished from those of less built-up areas by differences in air temperature, natural light, humidity, wind speed and direction, and amount of precipitation. These differences are attributable in large part to the altering of the natural terrain through the construction of artificial structures and surfaces. The altering of the natural terrain has influenced our health. For example, a study conducted by Palm showed that by 1700, over 90% of children in the industrialized cities of North America and Europe had some signs of rickets. A comparative trend was the relative absence of rickets in the developing world.2 The researchers explained this phenomenon as due to the narrow alleys in cities that prevented residents from getting natural sunlight. As sunlight is a potential source of vitamin D, the lack of sunlight contributed to the development of rickets from vitamin D deficiency.

Television has been one of the greatest inventions of all time and an integral part of urban life. But even the inventor of this would not have imagined in his weirdest dreams how grave an effect television would have on human health. With more and more children and adults spending the majority of their time in front of the television, they have been deprived of physical activity. In the more recent past, computers have come into the picture, but the story is the same as that of the TV. In fact, the increasing rate of juvenile obesity can likely be attributed to these one-eyed-monsters.

It won't be wrong to say urban life has become a life of illnesses. Previously urban life brought infectious diseases. Now, they are psychiatric illnesses. It has been estimated that in the coming few decades, psychiatric illnesses will take over as the most prevalent disease in the world. If we think for a moment, it is not difficult to see that along with urban development, crime rates have also soared. And it seems very realistic, especially with the current hectic lifestyle that most people lead, that one can hardly find any time for their family anymore, contributing to even greater levels of mental stress.

Encroachment over nature

Between 1982 and 1992, 19,000 square miles of otherwise rural cropland and wilderness were urbanized in the United States (World Resources Institute 1996). "We are simply converting more and more of the most fertile land areas to a non-productive state by covering them with parking lots and buildings that spread out over a larger and larger area," says Imhoff, biologist and remote sensing specialist at NASA's Goddard Space Flight Center.3 This is not the case with the United States alone, but is happening all over the world and even more rampantly in developing countries such as China.

Many of us might not be aware of the Aral Sea tragedy. In the 1960s, to irrigate land to grow cotton, the Soviet Union diverted the rivers  the Amu Darya and the Syr Darya - that fed the Aral Sea. Ever since, the Aral Sea has been steadily shrinking. By 2004, the sea had shrunk to 25% of its original surface area, and a nearly fivefold increase in salinity had killed most of its natural flora and fauna. By 2007 it had declined further to 10% of its original size, splitting into three separate lakes, two of which are too salty for fish to live in.4 This is how grave human intervention in nature could be. This act affected the fishing companies and hampered the economy of the area, leading to much poverty and suffering.

The burden of more people

Population growth is another aspect of urbanization. It took from the beginning of human history until 1800 to reach a population of one billion, 130 years to add one more billion and only 11 years to reach a population of six billion people globally. But, the amount of land remains same. It doesn't grow an inch. This is why the threat of a food crisis is looming over the world now. The rising population is in part linked to urbanization because of the evolution of more modern and efficient health services that often accompany cities, in contrast to the mediocre or even archaic health services of small, isolated communities. More people now have access to better healthcare because they live in or near large cities, and hence they are living longer. It really is no wonder a food crisis is threatening, as less land and more mouths means less food for each person.

Global warming: Mother Nature is sick

Another huge impact of urbanization is the rise in global temperature. Every time a house is built or a road is laid, local vegetation is uprooted. These days, greeneries are a rare sight in big cities. Normally plants take in carbon dioxide and use it as food. By decreasing the amount of carbon dioxide in the air, the earth is kept at a cooler temperature. With diminishing vegetation, the level of carbon dioxide in the atmosphere has increased and global temperature has soared. Furthermore, the numerous motor vehicles, which are an integral part of urban life, emit huge amounts of carbon dioxide which complicate the current situation which has already been made worse by decreasing vegetation. According to the Intergovernmental Panel on Climate Change (IPCC), the Earth's average surface temperature has increased between 0.4&deg;C (0.7&deg;F) to 0.8&deg;C (1.4&deg;F) over the last hundred years largely due to these gases. Over the next hundred or so years, it is feared that temperatures could rise another 1.4&deg;C (2.5&deg;F) to 5.8&deg;C (10&deg;F), causing sea levels to rise, rainfall patterns to change, and ecosystems to shift (IPCC 2001).2 It is not hard to imagine that this type of drastic temperature change will make life more difficult on earth.

Pollution: an ugly face of urbanisation

Pollution is what man has brought along with his urban ideas. Smokes, industrial wastes, non degradable plastic wastes, and life-threatening nuclear wastes have all accompanied urban development. Each year, commercial nuclear power plants in the US alone produce 3,000 tons of high-level waste which include spent nuclear fuel and reprocessed materials.5 The health hazards they have brought are the price we have to pay for so-called better living standards.

So, where's the problem then?

Politics has always been at the back of every change in human civilization. Politics is what has shaped the present day world and no doubt, it will continue to do so in the future. If we analyze the political activities to date, we can clearly see that many man-made disasters were the results of political power at play. Take the two world wars or present-day terrorism as examples. They are all the results of political disagreements. How many innocent people were killed in Hiroshima and Nagasaki? How many innocent lives were taken in the World Trade Centre terrorist attack? Big and powerful nations are in a race to acquire more power and conquer the world rather than trying to make it a safer and more peaceful place to live in.

Can we do anything?

What seems like a beautiful picture of a well organised, safe, clean urban life is not as picturesque as it appears. It also has an ugly face which has marred the beauty of human civilization. But we can change it. What we have taken from nature, we should return as well. We still have time and we can do it. However, it will take effort. We cannot just snap our fingers and expect everything to go back to normal. We have to act before it is too late. Let's wake up. Let's do whatever we can do. Let's start from our homes. Let's keep them clean. Let's keep our surroundings clean. Let's use public vehicles more than private ones. Let's make a habit of reusing and recycling. Let's cut down on our use of non-degradable products. Let's save trees instead of building more buildings. Let's save greeneries. In not anything, at least we can talk to each other about how we can make urbanization a safe and positive experience. Let's raise our voices and help the authorities make the correct decisions. It's our planet and our health and we have to save it. As the past vice-president of the USA, Mr. Al Gore, put it in his documentary "The Inconvenient Truth," let's not let our children say to us, "Why didn't you wake up when you still had a chance?"

References

1. Wilford JN. How Epidemics Helped Shape the Modern Metropolis. The New York Times 2008 Apr 15 2008.